We report here the formation of plasmid linear multimers promoted by the Red-system of phage lambda using a multicopy plasmid comprised of lambda red alpha and red beta genes, under the control of the lambda cI857 repressor. Our observations have revealed that the multimerization of plasmid DNA is dependent on the red beta and recA genes, suggesting a concerted role for these functions in the f...

We have developed a cell-free system from Escherichia coli for studying illegitimate recombination between nonhomologous DNA molecules. The recombination is stimulated by oxolinic acid, an inhibitor of DNA gyrase. The stimulation is abolished by coumermycin A1 and is not found in extracts of nalidixic acid-resistant (gyrA) mutants. We therefore inferred that DNA gyrase directly participates in ...

The repressor gene of the Lactobacillus phage A2 has the following properties: it (i) encodes a 224-residue polypeptide with DNA binding and RecA cleavage motifs, (ii) is expressed in lysogenic cultures, and (iii) confers superinfection immunity on the host. Adjacent, but divergently transcribed, lies another open reading frame whose product resembles the lambda Cro protein. In the 161-bp inter...

Cloning in lambda gt WES phage of EcoRI fragments from maize seedlings DNA led to the isolation of four fragments containing genes coding for 21000 dalton zein proteins. The zein genes, identified by electron microscopic analysis, do not contain intervening sequences detectable by this method. The flanking sequences were analyzed by restriction sites mapping and hybridization and showed areas o...

The structures of a series of plaque-forming metJB transducing phage were studied by restriction endonuclease mapping and enzyme activity assay. One of these phage, lambda pmet100, was inactivated by heat shock in the presence of EDTA, and deletion mutants were selected from the survivors. Two of these mutants, lambda pmet100 delta 1 and lambda pmet100 delta 2, were used to confirm the gene ord...

Infection of a sensitive host by the lambdoid coliphages can cause death of the bacterial cell by lysis or can lead to a lysogenic cell, with the viral DNA stably integrated into the host chromosome. These alternative responses both require the coordination of several host and phage functions, and lambda infection follows a well controlled developmental plan. The lytic and lysogenic pathways of...

limited number of mutually specific cohesive sites implied thereby suggests a specialized biological function, one that remains to be identified. Summary.-The DNA of phage lambda undergoes reversible transitions from linear to characteristically folded molecules, and from linear monomers to open polymers. Some conditions favoring one state or another have been defined. It may be surmised that e...